I. Kalantari et L. Welch, Recursive and nonextendible functions over the reals; filter foundation for recursive analysis. II, ANN PUR APP, 98(1-3), 1999, pp. 87-110
In this paper we continue our work of Kalantari and Welch (1998). There we
introduced machinery to produce a point-free approach to points and functio
ns on topological spaces and found conditions for both which lend themselve
s to effectivization. While we studied recursive points in that paper, here
, we present two useful classes of recursive functions on topological space
s, apply them to the reals, and find precise accounting for the nature of t
he properties of some examples that exist in the literature. We end with a
construction of a recursive function on a small subset of the unit interval
which is strongly nonextendible. (C) 1999 Elsevier Science B.V. All rights
reserved.